Which measures of adiposity are related to Australian adolescent's perception of their weight?

Aim To determine which measurement of adiposity - standardised body mass index (BMI-z), waist circumference or body fat percentage - is most closely correlated with adolescents' weight perception and whether this differs by gender. Methods Weight and height (used to calculate BMI-z), waist circumference and body fat percentage were measured in 2278 adolescents aged between 12 and 16 and compared with self-reported weight status. Results The distribution of subjects across the three weight categories (underweight, healthy weight and overweight) differed significantly between BMI-z, waist circumference and body fat percentage (p<0.001). BMI-z was most closely aligned with perceived weight status in boys and girls, and waist circumference was also a good correlate of weight perception in boys. Boys were more likely than girls to underestimate their weight when it was defined by BMI-z; however, girls were equally likely to underestimate their weight when it was defined by waist circumference. The majority of adolescents underestimated their weight status when it was defined by BF%. Conclusion BMI-z is the closest correlate of self-perceived weight status. In the absence of internationally accepted reference values for waist circumference, BMI-z is the most appropriate measure to verify weight perception.